How do you provle cos (pi-x) =- cosx?
1 Answer
Jan 30, 2016
see explanation
Explanation:
using the trig formula: cos(x-y) =cosxcosy + sinxsiny
hence
cos (pi - x) = cospicosx + sinpisinx now
cospi = -1 , sinpi = 0 then
cos(pi - x ) = -1 cosx + 0 = -cosx